1. Field of the Invention
The invention relates to a surveying system and, more particularly, to a surveying system having a sighting device and a position measuring unit, and also to surveying process using such a surveying system.
2. Description of Relevant Art
A surveying system of the given category is known, for example, from European Patent EP 0 481 307 A2. This document discloses a tachymeter with a GPS (Global Positioning System) position measuring unit; that is, a satellite-based position measuring unit, wherein both the sighting device, i.e., the tachymeter proper, and also the reflector rod to be sighted with the tachymeter, are equipped with a satellite-based position measuring device.
However, the satellite-based position measuring unit requires free lines of sight to at least four satellites. Thus the use of the satellite-based position measuring unit is limited or impossible between houses, in surveying from corners of houses, under trees, under bridges, in ravines, and in buildings.